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MIT Designs Less Expensive Fusion Reactor That Boosts Power Tenfold
jan_jes writes: Advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak (donut-shaped) fusion reactor. The stronger magnetic field makes it possible to produce the required magnetic confinement of the superhot plasma — that is, the working material of a fusion reaction — but in a much smaller device than those previously envisioned (abstract). The reduction in size, in turn, makes the whole system less expensive and faster to build, and also allows for some ingenious new features in the power plant design.
From T(first)FA: the major radius is 3.3 m and the minor radius is 1.1 m.
If it weren't for deadlines, nothing would be late.
Or have we upgraded to 19 years away now?
Does anyone want to venture a guess as to which will come first, the Year of Linux on the Desktop, or the widespread availability of this fusion reactor technology?
Damn it. That'll teach me not to read TFA before failing at first post.
People really need to understand that we are nowhere near dealing with the high energy neutrons a tokamak slings around and that such designs are purely for research in fusion physics and similar.
Thorium fissile reactors. That is where all of the money needs to go at the moment when it comes to power production, not solar or wind.
Still, it is good that research in that area is still ongoing. We need to find out pretty soon whether this planet has to go all-renewable in order to survive. Working fusion within the foreseeable future would be very much desirable.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
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Fusion power will be 20 years away until the governments of the world realize that Deuterium-Deuterium fusion doesn't actually "do" anything. Multiple stage, multiple fuel fusion is what we need. Start cold and go hot vs. start hot and then go cold. T3, D2-T3, then D2-D2.
And what's the thermal efficiency. i.e. power out/waste heat.
That seems to be the elephant in the room WRT fusion, producing 3x as much energy out as you push in won't help with global warming if you produce 100x as much waste heat as you do usable energy out.
It can't be that great if they think they'll be able to go from a 3:1->6:1 energy in to energy out just with engineering.
We'd just be replacing indirect heating of the atmosphere with direct heating.
This is good news, and I applaud any improvements that will shorten the time to commercial nuclear fusion... but...
It's clear to me that what we should do in the interim is develop thorium fuel cycles using LFTR and 4th (or is it 4.5?) generation nuclear fission reactors.
The thorium fuel cycle and liquid flouride thorium reactors are the clear fission winners, and would help clean up the mess that the Uranium fuel cycle has produced in the past, including processing all that 'used nuclear fuel' sitting in cooling ponds into viable starter fuel for the thorium reactors, and eventually into much safer fission products.
Smaller faster and cheaper, plus we already have it working.
-- Tigger warning: This post may contain tiggers! --
Afaik, the total amount of matter actually reacting at any given moment is less than a gram, if you cut that supply the reaction will auto-extinguish in micro-seconds.
Wow, but when you're still a million times away from breakeven, so what? Is there even a practically-demonstrated method of extracting the energy usefully from a fusion reaction?
I mean sure, you could put windmills in a circle around a H-bomb test....
Without confinement the fusion fails to sustain and the reaction stops working. That is the entire reason for the confinement, with no confinement it won't stay running. And confining a high energy reaction is difficult and takes a lot of energy.
The MIT Media Lab and especially Mr Marvin Minsky likes to scare people that they "can build a computer smarter than humans by 2001". Of course they have updated their scare message.
Now look at ANTs:
http://lingolex.com/ants.htm
I bet Mr Minsky can run something like 500 Neurons in realtime on his computers. Ants have 250000 neurons.
Why is he doing this and what is his pleasure in scaring unsuspecting human beings ?
What is his malicious agenda ?
Why has nobody kicked him out of his cushy job ?
I seriously wonder why this pervert guy is still part of MIT.
Regarding their improved Tokamak - is it a ploy to sabotage support for ITER ?
Given their less than stellar record, we must suspect this.
I really hope they get somewhere with this. I have some faith that if it is developed at MIT, the world will benefit if it works.
Contrast that to Lockheed which also has some pretty promising experimental fusion tech, but if it works, it will benefit no one except for a few fat cats, because it's fucking Lockheed.
"10x the output"
10x a negative number is still a negative number
that they called the new design an ARC reactor... I.E. Iron Man....
"I don't code the things you use, I make the code your things use better."®
So... a new donut-shaped nuclear reactor and no Simpsons/Homer Simpson reference yet?
I guess I'll make one by quoting South Park: "Simpsons did it!"
> see, fukushima
see, ghostbusters
good luck with that.
No, don't "see fukushima".
With fission, the challenge is stopping the reaction from running away. With fusion, the challenge is keeping it going. If you suddenly lose containment, what happens is that the hot plasma burns into the walls of the reactor, damaging them. Annnd.... that's it. There's a small amount of tritium there, but it's not a great amount, and tritium isn't that hazardous of a material compared to most radioactive elements. There's some induced radioactivity in the reactor, but it's quite limited because you can choose what to make the reactor out of (and iron's not all that bad for induced radioactivity anyway, it's generally the heavy stuff that's problematic). The lithium blanket is harmless (except for, again, breeding tritium - which is constantly removed). There's beryllium in there, but it's not dangerous when not in gas or dust form. Some work had looked into using lead as a neutron multiplier, which could have indirect breed polonium or other problematic compounds, but beryllium works a lot better than lead.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
that failure mode for fission reactors is from decay heat of fission products in the fuel. That problem doesn't exist with fusion in any form.
The plasma is essentially a (pretty good) vacuum. There's some fraction of a gram of material that is fusing by being squeezed into a thin ring within that vacuum. If you stop supplying power to the magnets, the vacuum becomes more uniform, the fusion stops and the machine ceases to produce heat.
There are failure modes with high-powered superconducting magnets that can produce large mechanical forces - some failures could physically wreck the reactor. Something like this happened at LHC and it cost a lot of money and time to repair. But, say you crack the fusion chamber; what will happen is air will go rushing in and the teaspoonful of hydrogen will escape. The battery in your car produces hydrogen in much larger quantities than are involved here. It's not like a science fiction show where glowing purple gas will fill the facility and melt people it touches.
Are you a troll, or just stupid?
The only efficient, earth-based source of the tritium needed for all working fusion reactor designs is a fission reactor. If you have a large enough fission reactor to power a fusion plant, it's producing far more energy than the fusion reactor can and is safer to handle if you do _not_ try to harvest the tritium, which is quite unstable itself.
The only other economically feasible source is solar sails, but they're similar to the fission source. They collect so much more radiative solar energy than can be harvested from the tritium they can gather, there is simply no point to engaging in the tricky task of harvesting the tritium.
TFA makes no mention of what happens if you stop supplying the energy required to confine the plasma. This could be a weak spot in the system.
It explodes in a 40MT blast. Didn't you see Aliens?
TenUNFOLD sounds morer.
TFA makes no mention of what happens if you stop supplying the energy required to confine the plasma.
Getting the right conditions for more-out-than-in fusion is REALLY HARD. So far it's pretty much only been done momentarily - using atomic fission bombs as working parts to apply enough heat and pressure.
So when there is ANY problem in the confinement, the fusion stops.
You're left with the energy in your plasma - several camera photoflashes' worth - and your superconducting magnet - which probably is unharmed and still running.
If the magnet is not properly quenched, at most it's got the energy of a large electrical fire or small bomb - on the rough order of a few hand grenades or laptop battery fires. This might be enough to throw around the small amount of low-level-radioactive material created by months or years of neutron bombardment of the reaction chamber walls and the like.
This is not in the same ballpark - by many orders of magnitude - as the few tons of molten, activated, coreium you'd get from an old-tech fission plant meltdown (all set to become an UNcontrolled, UNcooled, operating reactor if it manages to be puddled into a compact volume), or the fuel assemblies full of recent fission products still putting out, for months, heat enough to melt, ignite, or partially vaporize themselves if the coolant level drops enough to uncover them.
It's the difference between Fukushima or Chernobyl and, at most, a transformer fire in a warehouse with a substantial number of ionization smoke detectors installed.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
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Question for you. You seem quite knowledgeable about to tokamak fusion. If the entire reaction has to be surrounded by this high energy magnetic bottle to keep it going, how is the spent fuel removed and new fuel introduced? I understand currently they just shut down the field, but I've heard that it takes days to warm up and re-chill the magnets between runs. Seems a pretty big flaw to me.
It's only progress if it works. The field of fusion has a well established track record of reactor designs that do not work when built for one reason or another. I'll get excited when they have demonstrated that it works and not before.
TFA makes no mention of what happens if you stop supplying the energy required to confine the plasma. This could be a weak spot in the system.
It explodes in a 40MT blast. Didn't you see Aliens?
Yes, but I watched it from orbit. It was the only way to be sure.
Crumb's Corollary: Never bring a knife to a bun fight.
If you fail to contain the reaction it very rapidly dissipates. That's in fact the whole problem with this type of reactor design - no one (as of yet) has succeeded in keeping the plasma confined for long enough to generate more power than they put in to start the reaction.
Umm, no.
Tritium has a halflife of 12.3 years. Even U235 has a half life of 700 megayears. In other words, tritium is intensely radioactive compared to uranium (or most natural radioactives).
Note also that uranium is an alpha emitter. You can protect yourself from it by wrapping it in old newspaper. It takes (slightly) more to keep tritium from being a problem (say, three sheets of newspaper)....
"I do not agree with what you say, but I will defend to the death your right to say it"
Tokamaks are so unworkable that even a tenfold improvement leaves them wanting. My money's on Lockheed's design: https://en.wikipedia.org/wiki/...
That that is is that that that that is not is not.
The real question is: will fusion achieve real energy production before our civilization collapse because of power source exhaustionN
Neutrinos don't interact with matter very much at all. Like to the point that it took abandoned mines full of water to catch enough of the neutrino blast coming from the sun ALL THE TIME to make enough blinks to finally prove they really exist.
Homestake Mine experiment: The chlorine in 100,000 GALLONS of C2Cl4 liquid caught about ONE electron neutrino every two DAYS. Even if you're a real couch potato you're a lot smaller target than that big tank - like by four orders of magnitude, which will swamp variations in the neutrino-interaction cross-sections of your various elements. You might catch more than one electron neutrino in your lifetime, but not many more.
Measured value for the solar constant (total energy from the sun going through an area of space at the Earth's orbit - roughly that area's share of the energy delivered by the sun's fusion) is 1.361 kW per square meter. Area of a sphere is 4 pi r^2. So let's be pessimistic and assume a fusion power plant turns one part in four pi of the fusion energy into deliverable power. (It will probably be closer to 60%) A 1.361 kW generator (enough to run your house) a meter away would be about as "bright" as the sun, neutrino-wise. A 1.36 GW power plant (enough for a million houses) a kilometer away, ditto.
One nice thing about low, constant, levels of ionizing radiation is that they actually slightly REDUCE the incidence of cancer and the like. (This is part of why Denver residents don't have horrible cancer rates compared to those living nearer sea level.) Apparently the ionizing radiation provokes the production of inducible enzymes that repair DNA and scavenge free radicals - preventing more damage from both radiation and free radicals from the cell's own energy production than the radiation causes. Up to the saturation of the induciblity it's a slight net gain. Unfortunately, the neutrino flux from fusion reactors would be too low to confer this benefit.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Contrats, of all of the many thousands of radioactive isotopes created by man or nature, you picked the one with the 32nd longest known half life. Try compared to nuclides in general.
There's a balance in terms of half life. The shorter the half life, the more intense the radiation - but the shorter you have to deal with the problem. The longer the half life, the less intense the radiation, but the longer you have to deal with the problem. The only way around this is a product that has a very low energy in its radioactive decay. And indeed, that's just what tritium is .
Tritium's decay energy is only 18.591 keV, which is tiny by the standards of radioactive decay - by comparison, U235's decay energy is 4678 keV - 251 times more intense. Furthermore, alpha radiation, while harmless outside the body (like tritium's ultra-weak beta), is (unlike beta) terrible inside it - its biological effectiveness is 20x that of beta. Hence a decay from a atom of U235 inside of you is 5032 times more damaging than a 18.591keV electron (beta). On top of this, you have biological half lives. Uranium's is only slightly longer than tritium's, 15 days instead of 12. But, again, U235 is not normally a problematic radioisotope. 239Pu, 90Sr, 226Ra, 45Ca, etc have biological half lives so long that they're effectively with you until they decay or you die. Oh, and on top of all of this? All of the energy of beta decay doesn't go into the electron; a higher percentage goes into the muon antineutrino, which escapes harmlessly off into space. The average energy of the beta particle from tritium decay is only 5.694 keV. Net result? Before controlling for the difference in half life, U235 is 20540 times worse for the body than tritium.
Now, of course, due to 235U's incredibly long half life, its radioactivity rarely a problem - which is why fresh fuel rods are not considered very dangerous, but spent ones are. People's concerns in nuclear accidents center around the fission products: strontium, iodine, plutonium, etc - things with shorter (but still problematically long) half lives and strong biological effectiveness. Versus them, the ridiculously low energy tritium is almost irrelevant in terms of biological effect, even if present in similar quantities. Combined with the very small amount of tritium that's in the torus at any point in time, it's just simply not even remotely comparable.
Did I even bother to mention that gaseous tritium tends to rapidly escape wherever it is and ascend up and out of the atmosphere? Tritium in the form of heavy water can be problematic in higher quantities, but of course, there's no "higher quantities" of any form of tritium in the torus.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
At the ICOPS conference (International Conference on Plasma Science) I asked a couple of professors what they thought of this.
They thought it was pretty telling that Lockheed wasn't investing a lot more money in this concept than they are.
If Lockheed isn't putting significant money into it, maybe you should think twice about putting your money (figuratively speaking) into it.....
That said, I really hope Lockheed does succeed with this, and starts shipping units like crazy and displacing coal power production worldwide.
--PM
The goal of a fusion reactor is to generate energy. If it does not generate energy then it does not work.
Grandparent said 'hazardous', not radioactive, so he's still correct. While tritium certainly radiates more than uranium, it's decay products are fairly low energy and don't pose any immediate health hazards.
Tritium doesn't bioaccumulate significantly (10 day biological half life), unlike Strontium and Iodine isotopes.
Injection is relatively easy; one uses pellet injectors. They basically bore tiny pellets of a mixture of deuterium and tritium ice and shoot them into the middle of the core with a tiny gas gun.
Removing the helium "ash" is harder, and requires something called a divertor. The plasma naturally pushes the helium toward the outside, as it's heavier. The divertor basically juts out into the outer edge of the plasma stream and skims off the plasma, acting as sort of an exhaust system. But it's an incredibly hostile environment, and not just because the temperature (it has to operate continuously at thousands of degrees, and that's after water cooling!) - it's being pelted by high energy alphas all the time! Regardless, it provides not just a way to get rid of helium but takes up many megawatts of heat that are used for power generation.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
...in a big city connected to the Internet of Things.
The problem with fiction is that reality is so much more astounding!
It would be interesting to compute what the effect of using this tape, rather than copper windings, would have on the scale of Bussard's/EMC2's polywell fusion machine prototypes. The Polywell is essentially a big gassy vacuum tube that produces fusion-powered electricity from hydrogen and boron.
The proposed 100 MW machine is 3 meters (about 6 1/2 feet) in diameter - because the scaling rules (5th power) include both volume and mag field strength, which both go by power laws (3rd and 4th respectively) of the radius. Their sweet spot is 1.5 meters - about the size and power density of a Boeing 777's engine - with too little power produced if much smaller, needing impossible material strengths if much larger. A machine this size, peripherals and all, would fit in one store segment of a strip mall and power a small city.
But their prototypes so far have used copper magnetic windings and pulse operation. It's not clear to me whether these engineering numbers include superconducting magnets - and if they do, whether they use windings as good as this tape or something more akin to the IETR.
A 5 kW "Mr Fusion" about the size of a home furnace would finish off the power grid. A 20kW version the size of a microwave oven would run automobiles without the need for recharging.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Never mind things that already work such as, wind and solar, as well as things that likely will such tidal pools.
Put all your money in something that m-i-g-h-t someday work.
https://www.youtube.com/c/BrendaEM
Still gonna make waste.
https://www.youtube.com/c/BrendaEM
The smaller designs, including L-M, Polywell, and Tri-Alpha are much more likely to end up in commercial designs than tokamaks.
Then there's this guy, who has an interesting laser-driven design. It has however a tiny problem in that it uses pulsed magnetic fields of ~ 10kT.
That's in fact the whole problem with this type of reactor design - no one (as of yet) has succeeded in keeping the plasma confined for long enough to generate more power than they put in to start the reaction.
Actually I understand that one of 'em recently DID reach theoretical breakeven (more fusion energy produced than input energy consumed) for a moment.
But that's still a "factor of several" from ENGINEERING breakeven (more put into the grid than pulled from it). There's still a long way to go.
Not counting fusion bombs, of course. Batch processes are a LOT easier than flow. B-)
That's one of the reasons they keep trying to do ignition with lasers. If they could trigger a fusion bomb without using a fission bomb for a primer, they could bury it, set it off, use the hot hole to make steam for a while (geothermal style), then drop in another one and repeat...
Unfortunately, somebody could also skip making the hole and just set it off in a city. So the tech would be kept under tight government control. Non-batch processes would not need such tight regulation.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Thank you. I've asked that question before and never got an answer. I always assumed that smarter folks than me had figured it out or they wouldn't be building the ITER.
fusion has a problem of fast neutrons. pretty much nothing can stop them, even layers of lead will become contaminated pretty quickly. In other words, once the fusion reactor starts operating, no living thing will be able to go anywhere near it, practically forever.
Is the whole thing cleaner than fission? very likely... the reactor itself becomes radioactive "waste" after its lifetime, as opposed to all the crap the fission reactor creates.
see, fukushima
For what? An example of the damage that can occur when the magnetic containment system in a fusion reactor fails?
..Mullah or Pope, Preacher or Poet, who was it wrote: "Give any one species too much rope and they'll fuck it up"?
Thanks Rei! Google of course makes it easy to research stuff (if you know what you're looking for) so I find comments like yours very helpful for steering further research in addition to the intrinsic educational value of your posts.
..Mullah or Pope, Preacher or Poet, who was it wrote: "Give any one species too much rope and they'll fuck it up"?
A cynic would say that researcher will research if there's grant attached to it. If there's no money in it - it's a hobby. Therefore Lockheed design could be a good design but we will never know with that kind of attitude.
Unfortunately, somebody could also skip making the hole and just set it off in a city.
Honest question, I think I'm missing something - wouldn't that require the construction of a NIF-level facility at the target site or a similarly-powerful orbital platform aiming its lasers at whatever hohlraum-equivalent you've dropped on the city?
..Mullah or Pope, Preacher or Poet, who was it wrote: "Give any one species too much rope and they'll fuck it up"?
Looks like a very interesting article, but when I saw the phrase "ARC Reactor", was I the only one who thought this was an Iron Man joke?
Admit that you are/were wrong and move on. Right know you're just looking butthurt and snide.
So you asked some science professors about a technical design and they replied with an assessment based not on technical issues, but based on assumptions about Lockheed's internal management priorities and economics.
That means they don't have anything bad to say about the design itself then, and since they are not experts on economics or Lockheed's management priorities you can safely ignore their smug assessments of stuff they know nothing about. That shit is the curse of professordom. Smart at one thing doesn't imply smart at everything, and "if I ran Lockheed Martin" is a bad party game, not an intellectual pursuit.
Anyway I thought we'd abandoned this "twice as much money makes projects move twice as fast" bullshit in the 70s, to the extent that it's now cliched to point out that two women can't have a baby in 4.5 months. And the whole point of the LM design is to reduce iterative research costs, so low research costs indicate success, not failure.
Hazard of a radioactive material isn't merely how "hot" it is, but also how biologically active it is. Radium, while outside the body, isn't a particular problem (IIRC an alpha emitter), if it gets inside you your body uses it like calcium so it stays in your bones, irradiating you from the inside, for a large amount of time. Tritium on the other hand doesn't linger in the body, it remains for a fairly short time period, so ends up being a lot less dangerous than some much-less-hot radioactive elements that would end up getting incorporated in the body.
Oolite: Elite-like game. For Mac, Linux and Windows
Fusion's 17 MeV neutrons are nothing compared to spallation's neutrons, which can approach (or in some designs even exceed) a GeV. 17MeV neutrons are most eminantly stoppable. Yes, they have a longer penetration distance, and yes, there are some differences in behavior (they tend to cause (n,2n), (n,alpha), (n,d) etc reactions a lot more often while lower energy neutrons usually only do (n,gamma) transmutation), But these are not fundamental differences nor fundamental problems.
Fusion reactors do not use "layers of lead" as shielding. You have some misconceptions about how shielding works. Lead is an excellent shielding material for gamma and beta, but it's terrible for neutrons. It does not moderate them down at any relevant rate due to its high atomic mass, it has a low (n, gamma) gross section, and when it does undergo neutron capture it breeds bismuth - which is fine, except when bismuth undergoes (n, gamma) it breeds polonium, which is really, really nasty stuff. There's also a variety of other neutron reactions lead can undergo which lead to other radioactive products. You don't use lead for neutron shielding. Quite to the contrary, lead is used as a coolant in some types of nuclear reactors because of how little it interferes with neutrons.
Neutrons by contrast are generally best blocked by light elements. Hydrogen is the most effective moderator, although you want both to moderate down the neutron energy and have a high neutron cross section. And of course you don't use pure hydrogen because that's an explosion hazard. So if you want liquid shielding, something like borated water is your best bet. For solids, borated plastics are best.
However, the neutrons in a fusion reactor are not seen as an undesirable thing, but as a critical part of the process to keep it going. Because you need tritium to run it, and tritium doesn't grow on trees, you have to breed it. D-T gives one neutron and it takes one neutron to make one tritium, so if you didn't have any neutron multiplication, the *best* you could possibly do (with no losses and 100% capture) would be breakeven. The reality is that you have to do neutron multiplication to get enough to operate. So the reactors use a lithium-beryllium blanket, of a thickness to absorb the overwhelming majority of the neutrons. Outside of this there will always be stray neutrons that escape, you're not going to want to just stand next to the thing, but it's not going to be a Glowing Ball of Death.
Now, obviously, for structural materials, you're not going to be building it out of borated water, borated plastic, or lithium. Beryllium, mind you, is light and an excellent structural material, but it's super-expensive and difficult to work with, so it's only generally used structurally in key areas. Aluminum (better, lithium-aluminum) is great and undergoes almost no induced radioactivity, but its low melting point limits its use in high temperature applications. Graphite would be great, and is great in some cases - but it undergoes Wigner energy problems if not operated at high enough of a temperature. Composites, which aren't as Wigner energy sensitive, usually can't take the heat. So altogether, one generally deals with iron alloys (steels), with the alloying agents chosen based on what gives the desired properties while undergoing the least problematic transmutation reactions. With proper design, the level of transmutation can be kept pretty low.
Why would it be low? Well, the vast majority of iron is 56 iron. There are also a few percent of 54Fe, 57Fe, and a fraction of a percent of 58Fe. Let's trace the neutron capture paths here.
54Fe becomes 55Fe. This is radioactive, but the half life is only 2,7 years - hardly "forever". It decays to 55Mn, which is stable. If during the 2,7 years average it captures another neutron, it becomes the common 56Fe. If the 55Mn captures a neutron, it becomes 56Mn. 56Mn is radioactive but only has a halflife of 2,6 hours. It decays into 56Fe. So either way we get back to 56Fe with no long-lived product
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
Ugh... that should read 14 MeV neutrons, not 17.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
Actually, the holy grail of fusion is aneutronic fusion. There's a group working on it that is literally doing their experiments in a garage in Jersey, and they have already exceeded the technical landmarks of the multi-billion dollar ITER in only a very short time. All other power generation designs require that we still use a heat engine to create electricity. The Aneutronic Fusion gives off massively charged 'jets' of positively and negatively charged streams which can be captured to generate electricity DIRECTLY. No conversion losses. It's also got the 'side effect' of using one of those jets of charged particles as thrust.. as in put it on a spacecraft and reach intra-solar bodies in weeks or months. Oh, it's also got the advantage of not giving off neutron radiation. at all. In fact, they are stating that after shutting it down you could safely walk into the reaction area in 30 min or so.
To me, THIS and a LFTR reactor working together would be the best possible power generation going forward. The benefits you could from a really hot LFTR reactor for making liquid fuels from C02, burning up old 'spent' fuel from conventional fission reactors and for the medical isotopes it generates just makes too much sense NOT to use them.
If I sound stupid, it's not me talking....
1 kw coal generates 5 times the electricity in a year that 1 kw solar does.
Is a pound of feathers lighter than a pound of iron too?
Considering what's at stake, that is, the promise of almost limitless clean energy, how is it that the U.S.A. isn't leading the world in an Apollo to the moon, first atomic bomb, Panama Canal etc... like effort to develop a usable fusion reactor. Yes, it would cost a lot but so what. The payoff would be priceless. Are the oil and coal companys paying off politicians to block it? I really don't get it.
they have already exceeded the technical landmarks of the multi-billion dollar ITER in only a very short time.
Exactly which "technical landmarks"? They've exceed the Lawson criterion and achieved more power out than heating & drive power in?
Or are you thinking of one of the couple pieces about aneutronic fusion designs that set some sort of temperature record? Getting high temperatures is not difficult, especially for a fraction of a second, and there are a lot of non-fusion research devices that greatly exceed the temperatures in fusion research. The hard part is getting a high enough combination of temperature, density, and confinement time (i.e. the Lawson criterion) that you can actually do something useful with it, and this is much, much harder than getting even two out of three. Many projects can already do two, even ones that died from lack of progress or fundamental problems.
Uranium is chemically TOXIC, as are most of its decay products. That turns out to be a much more immediate issue in health concerns. Toxic metal dust in your lungs a few extra clicks on the gieger counter.
But a cup of feathers is lighter than a cup of iron.
Whoosh! You missed the joke.
You should learn the difference between kw and kwh and why kwh is used to compare actual electfical production.
You should learn to laugh a little at a joke. Lighten up. A watt is a watt - hence the joke. I'm quite well aware of the difference between a watt and a joule so your response cracks me up.
But since you wanted to be pedantic, saying a "watt of solar" is a meaningless statement unless you clarify it further. Solar is a process that can mean many different things ranging from photovoltaics to photosynthesis. Coal is group of hydrocarbon chemicals with well defined properties but is essentially stored chemical energy viewed abstractly. Ironically coal really is just sunlight turned into hydrocarbons. If you want to talk about electrical power generated from burning coal versus power generated from photovoltaic cells then say so. Clarify what you are comparing or just stand back and laugh at the joke.
If you want to talk about efficiency (the amount of sunlight energy converted into electrical energy vs coal) then you have a discussion but coal does not have a 5X advantage there. If you want to compare energy densities then you probably aren't really comparing sunlight to coal because you are comparing storage mediums. You are probably comparing chemical batteries to coal which is quite different.
even a tenfold improvement leaves them wanting.
FTFA: "Right now, as designed, the reactor should be capable of producing about three times as much electricity as is needed to keep it running, but the design could probably be improved to increase that proportion to about five or six times"
My money's on Lockheed's design
Lockheed's design does indeed look pretty cool, but keep in mind that it counts as 100% vaporware at this point. By comparison, tokomaks count as a mature, fairly well understood technology. Making them net positive counts as merely an engineering problem, not a feat that requires invoking any groundbreaking new physics (and indeed, this new MIT design should prove net positive thanks to advances in largely unrelated materials science).
I sat in on a talk by Professor Steve Cowley (CEO of the UK Atomic Energy Authority, and head of the Culham Centre for Fusion Energy) not too long ago. When asked about this, he said he knew the guy leading the project at LockMart, he was a good guy, interesting concept yadayada.
But there was one important caveat: the LockMart team haven't even achieved first plasma yet.
That -- and stuff like magnet quenches, mechanical buckling due to Lorentz forces, etc etc; but agreed, remarkably safe, even compared to coal-fired power stations.
Tritium obligingly heads for the upper atmosphere when it gets loose.
"The sun was too far away from my solar panels, so I built a closer sun."
"Advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak (donut-shaped) fusion reactor."
Expected launch date: 20 years.
"Using these new commercially available superconductors, rare-earth barium copper oxide (REBCO) superconducting tapes, to produce high-magnetic field coils “just ripples through the whole design,” says Dennis Whyte, a professor of Nuclear Science and Engineering and director of MIT’s Plasma Science and Fusion Center. “It changes the whole thing.”
Anyone tried strapping this tape to the bottom of a skateboard yet?
If we could use the better wire to increase the field (fourth power), trade that away entirely for size scale-down, and leave the plasma density the same so we take the full hit there (third power):
- A 10:1 scale-down gives you a reaction chamber just under a foot across that gives you 100 kW. Home power, car power (75 HP continuous - you need about 20 plus "peaking" for a practical car), maybe trucks with slightly larger scaling.
- A 100:1 scale-down gives you a reaction chamber just under an inch across that gives you 100W. That would give you a power brick to charge-run your laptop or whatever.
All assuming the shielding and peripheral equipment doesn't bloat it or make it too heavy. Looks OK for home power, unlikely for laptop bricks (though maybe portable gasoline generators could go nuclear), somewhere in the middle for cars and trucks.
Nuclear dragsters! Neat! If the magnets don't stick them together or push them apart and off the track, of course. And if you can keep the stray neutrons in. (They'd use hydrogen-1/boron-11, where the main reaction is aneutronic, but that DOES have a little neutron emission from occasional side-reactions involving the "exhaust" nucleii, unstable carbon-12 intermediate step, and/or impurities.)
Now I REALLY want to know what magnet technology EMC2 is assuming.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Now practical fusion power is only 20 to 25 years away.
Again.
Still.
There's no time like the present. Well, the past used to be.
That's one of the reasons they keep trying to do ignition with lasers. If they could trigger a fusion bomb without using a fission bomb for a primer, they could bury it, set it off, use the hot hole to make steam for a while (geothermal style), then drop in another one and repeat...
Unfortunately, somebody could also skip making the hole and just set it off in a city. So the tech would be kept under tight government control. Non-batch processes would not need such tight regulation.
There are many orders of magnitude difference between the energy released by a fusion bomb and the target of something like NIF, or even the hypothetical power plant based on ICF. The target would not be buried in a hole, but inside a vacuum vessel. And it doesn't just scale up, because you would need much more laser power (as in city sized at that point) and would need careful access to most sides of the target. It won't be a threat to a city to require something the size of a city to be built by a major industrial power on site...
And your reply is the exact type of reply we need more of on /.. And the GP's reply...well, let's just say /. is missing a feature for me to mute selected people, as well as the people who modded them up.
oh lord... You could have looked it up. Even the big arse ITER contains less than a gram of material. Loss of confinement creates a mark and a little sputtering damage on the first wall or divertor plate. In fact it happens all the time.
If information wants to be free, why does my internet connection cost so much?
right now tokamaks are a factor of 2 away from working. A 10 fold increase in confinement would make them trivial to build. You could probably not even other with neutral beam injection.
If information wants to be free, why does my internet connection cost so much?
So, with this great advancement, hot fusion is no longer permanently 30 years in the future, but only permanently 20?
Yeh, like you have money...
HEY! reasonably intelligent and well-informed discussions are a clear violation of slashdot.
wake up and hold your nose
Pretty much by any reasonable metric, e.g. Q or Lawson criterion, tokamaks are still an order of magnitude or more away from being usable for power production. A factor of 2 improvement might get you a Q of above 1, meaning fusion reactions output more power than the heating sources, but that is still a long ways from an engineering Q, that takes into account that only ~20% of the power is removed by neutrons, efficiencies in conversion to electrical power, and other operations (e.g. magnets).
And NBI is likely going to stay, because it is not just about bulk heating, but about modifying the density and current profiles to get bootstrap current. This current is critical to long time scale operation of a tokamak, as otherwise you run out of flux if driving current via a transformer.
Loss of confinement creates a mark and a little sputtering damage on the first wall or divertor plate. In fact it happens all the time.
ITER is going to be a big step up in scale compared to current tokamaks, and enter a regime later in its operation where loss of confinement will not be acceptable. This won't level the building or anything dangerous to personnel more so than any other industrial setting. But the potential for equipment damage will be much higher, with possibility of puncturing vacuum vessel and cryostats with runaway electrons, or major damage to cooling system of the first wall, or even mechanical damage from induced currents in conducting structural elements. Disruption mitigation is close to top priority of issues on ITER, and something that has to be nearly flawless once it moves on from the first couple years of testing. There is concern that a single major disruption at higher operating conditions could put ITER out of commission for months or a year to deal with repairs.
0_0
News for nerds.....your post is one of the rare times I've been f'ing lost reading a COMMENT.
I'm amused.
Your mind is like a parachute. It works best when it's been opened.